News and information about wildlife in and around the parish

Ash dieback and pollarding

Several people have expressed concern at the number of mature trees that have been felled or pollarded recently in the upper part of the village.  Sadly, it is a sight that we will have to get used to since most of the trees involved are ash trees and most of them will have been infected with ash dieback- a disease that will kill some 90% of ash trees over the next few years.  You can find out more about dieback here.

Trees affected by dieback can become brittle and unstable and can shed branches in windy conditions.  Where such a tree is alongside a road or path the landowner needs to take action to protect themselves and the public – they would be negligent not to.  Trees well away from public access can be left to die since standing dead wood is a valuable wildlife habitat.

Pollarding – the removal of upper branches – is a long-established form of management and can preserve an ash tree for a time while making it safe. In most cases it will regrow until it finally succumbs to the disease and even then the trunk can be left standing for the benefit of wildlife.

A diseased tree may be weakened internally without signs showing on the outside.  For that reason the safest method of dealing with them is often with giant mechanical shears driven from a heavy vehicle.  The result may not be elegant but it is effective.  Some people have asked whether the brash from infected trees should be burned to slow the spread of the disease.  Unfortunately there are already billions of fungal spores circulating in the air and on leaves that dropped in the autumn so that would have little effect.

Ash dieback will bring about dramatic changes to our local landscape.  Since for environmental reasons we need to increase rather than reduce the number of trees across the country the parish council has established a tree group to help promote awareness of the situation and take practical steps to increase tree planting.  We have compiled information on how to recognise ash dieback, on what sorts of trees might make suitable replacements for ash and where to look for further advice.  We have also established a tree nursery to grow on native trees and begun to plant young trees to replace those that we will lose.

You can find out more about our activities by looking on the website here.  We would be pleased to hear from anyone who is interested in helping us or simply finding out more.

Garden Butterfly Survey sheets for 2021

Peacock butterfly as seen in Westbury flying on 2nd February 2021.  Another was seen on 8th January and was barely able to fly!  They hibernate as adults in sheds and wood piles and can come out at any time during the winter if there is a sunny warm spell.  They will have returned to hibernation quite quickly at the moment.

Butterfly Recording in Westbury Gardens:  a number of people have been recording the butterflies they see in their gardens each week from Week 1 starting on the 1st April to week 26 starting on 23rd September.   The scheme started in 2006, so there is an increasingly long run of data.  If you want to join in download the attached two forms – April to June, and July to September.  At any suitable day in the week count the largest number of each species of butterfly that you see in your garden at any one time.  This means that you cannot count the same one twice.  For example you might see 4 meadow browns and one small tortoiseshells on the lavender one afternoon and the next day 3 small tortoiseshells and a meadow brown on the same lavender. You would put 4 for meadow browns and 3 for small tortoiseshells in the week of the observations onto your sheet.  Return the sheet to Peter Bright at the end of September either in digital form or as a piece of paper.  peterbright60@btinternet.com

2021 April to June Blank recording form      2021 July to September Blank recording form

Pheasant on the feeders

One of seven regular visitors to the garden this winter. Seems to be a hen party, no males around so far.

2021 Westbury calendars – still a few left

This morning there were just 12 calendars left in the Community Shop.

The 2021 edition features excellent photos of local wildlife taken by members of the village Wildlife WhatsApp group

Remember that 100% of the £7 goes to support the shop.

PS: If you’d like to join the Wildlife WhatsApp group, leave a comment below.

Southern hawker laying eggs in pondside vegetation

One of Westbury’s commonest dragonflies.  Males, which are mainly blue, often swarm in large numbers.

2019 was a particularly good year for them.

Westbury Hawkmoths for the Week 9th September 2020

The Hawkmoths, Sphingidae are a widespread family of moths with more than a thousand species worldwide.  They are usually large, broad-bodied strong flying moths whose caterpillars have a characteristic tail spike.  Some members of the group have long tongues and feed extensively being able to use long tubular flowers as nectar sources, while others have reduced mouthparts and so do not feed as adults.  In Britain there are 9 species that are resident and a further 8 others that are more or less regular immigrants, but which do not successfully over winter. In the Parish in the last few years 8 species have been seen that I have heard about, though only the Hummingbird and Elephant Hawkmoths are seen every year.  Additionally, the Small Elephant Hawkmoth has been seen but not for a long time.  The Hummingbird Hawkmoth was covered in this series on 5th August.

 

Elephant Hawkmoth

Elephant Hawkmoth:  This characteristically ‘pink with olive markings’ moth has a long tongue and can feed easily from flowers like honeysuckle.  It can be seen on the wing from May until early August.  The usual caterpillar food plants are various willow-herbs and in gardens Fuchsias.

The large caterpillar, which is seen quite often, has two pairs of large eyespots on the  segments just behind the small head, which, on being disturbed, it waves about, perhaps startling a would-be predator.  The caterpillar forms a pupa in the leaf litter or in the soil below the food plant where it then over winters.

 

 

 

Privet Hawkmoth

Privet Hawkmoth:  This is the largest of our resident hawkmoths with dark chocolate coloured forewings.  It flies in June and July but does not feed.  The caterpillar food plants are wild and garden privet, ash, and lilac.  The caterpillar itself, is bright green with conspicuous purple edged white chevrons.  It can be found from July through to September and overwinters as a pupa sometimes over two winters.

 

 

Poplar Hawkmoth

 Poplar Hawkmoth:  This moth flies between May and July and can have a small second generation in August or September.  Its wings are a patchwork of brown and grey and at rest holds its wings such that the hind wing projects beyond the front edge of the forewing.  The eyed hawkmoth.  The food plants of the caterpillars is a variety of poplars and willows.  The caterpillar is green with white diagonal striping also similar to the Eyed Hawkmoth.  Pupae are formed buried in the soil at the bottom of the food plant, and which then overwinters.

Eyed Hawkmoth

 

Eyed Hawkmoth:  This moth flies from mid-May into July.  Its resting position resembles the poplar hawkmoth but if gently disturbed it reveals big ‘eyes’ on its hind wings and rocks too and fro.  This seems to ward off insectivorous birds.  The caterpillar food plant is predominantly apple but also crab apple and willows.  The caterpillar is green with pale diagonal stripes resembling the poplar hawk moth and can be found from July through to September or October.  It pupates underground near the food plant where it overwinters.

 

 

 

 

Convolvulus Hawkmoth found dead.

Convolvulus Hawkmoth:  This is the biggest of the hawkmoths mentioned so far.  It is an immigrant with very variable numbers arriving mainly in late August through into November.  It has an exceptionally long tongue and can feed easily on long tubular flowers, white, nocturnally scented ones seem particularly attractive.  The fore wings are mottled in ash greys and there are pink markings along the abdomen resembling those in the Privet Hawkmoth.  The larval food plants are various bindweeds and larvae are regularly found along the south coasts of the UK.  However, they do not survive to over winter.

 

 

full grown caterpillar

Death’s Head Hawkmoth: This is the rarest of Westbury’s Hawkmoths being seen only very occasionally. In 2019 11 caterpillars or pupae were found in Westbury and several were kept and emerged in captivity for people to enjoy seeing before release.  This year, at least so far, none have been seen, but they have been seen in Westbury before, as they are shown in a photo of the Village postmaster in what is believed to be 1984.

Westbury Postmaster

As the largest British Hawkmoth, it is quite unmistakeable with dark patterned forewings and yellow underwings with black borders.  The thorax has a very realistic looking skull like marking.  Small numbers arrive in the UK from strongholds in North Africa and southern Europe every year.  They lay eggs usually on potatoes but also on woody nightshade and the huge yellow caterpillars that grow rapidly can be found in August when lifting potatoes, or the large pupae may be found later buried in the soil amongst the potato plants.

Pupa

The 11 from Westbury and, for that matter, the 5 from Easton might represent eggs laid by a single fertile wandering female who has flown in from North Africa.  She spreads here eggs out between potato patches.   The adults emerge a month of so later in September and are occasionally seen.  They can enter bee-hives without being attacked, where their short tongues are able to feed on honey stores.  If the adult moth is disturbed it squeaks which may be part of its defences against attack by bees when it is in a hive.  The squeak might resemble sounds made by queen bees.  Neither the adults nor the pupae can over-winter in the UK and it is probably entirely wishful thinking to hope that the spectacular, newly emerged moths might fly southwards to return to southern Europe and North Africa.

in hand

 

Taking flight

 

Photos

Gill Cook

Liza Hobbs

Sylvia Healey

Ian Jones

Mike Jones

Peter Bright

Butterfly of the Week 2nd September 2020

Typical form

 

Clouded Yellow:  This is a ‘white’ and so is closely related to the Large and Small Whites, Orange Tip and Brimstone.  It is another migrant that, while it breeds over the summer in the UK, fails to over-winter except in very small numbers along the UK’s sheltered south coasts – the Isle of Wight and Dorset.  As with the Painted Lady its permanent population is in North Africa and Southern Europe.  Each year very variable numbers head northwards spreading out across Europe and Asia.  They usually arrive in the UK in late May.  The food plants of the caterpillars are members of the Pea family, particularly Clovers and Lucerne.  In good years they can produce three generations but more usually two with adults appearing in August and then again in October.  There is evidence of a return migration but not in the ‘clouds’ in which they can arrive in good years.  The last ‘Clouded Yellow year’ was 2013 but they only appear in Westbury Gardens very occasionally and in most years not at all.  The most likely place to see them in the Parish is on the top of the Mendips nectaring on knapweeds and scabious before flying onwards.  It could be that there is limited growth of the fodder crops, Clover and Lucerne, locally, and so there is little opportunity for numbers to build up nearby, even in years of abundant immigration.

Form ‘helice’

The butterfly is Small White sized but of more sturdy build and is a very strong flier being able to cross long distances over the sea.  The typical form is a very distinctive golden yellow but about 10% of the females are a much paler yellow – called ‘helice’.  These can easily be confused at a distance with brimstones and the other whites but the heavy dark markings around the edges of the wings are diagnostic.  However, when the butterfly settles it almost always settles with wings closed so it is rare to see these distinctive upper surfaces except in flight.

Photos   John Ball

Butterfly of the Week 26th August 2020

Male Wall

Wall:  This is another ‘brown’ and, like its relatives, its caterpillars are grass feeders.  However, it needs sparse, open, grassy areas with bare patches where sunshine enables the butterfly to bask and warm quickly.  It is a strong flier in these exposed habitats.  The male has a thickened dark area on its forewings which are the sex brands.  In inland areas of UK, in times past, it used to be common but has now become rare, only remaining relatively common at coastal sites around England, Wales, southern Scotland and Ireland.  It occurs in small numbers on Westbury Beacon and along the Mendips but in much larger numbers on Brean Down.  It does occur in Westbury gardens, perhaps one or two a year, and this year it has been seen on Broadhay during our particularly sunny and warm May.  Typically, it has two generations a year with the first emerging in late April or early May.  The eggs laid by this generation will go through their life history to emerge in July or August.  The offspring of this second generation need to get to the third instar caterpillar stage at which it is then able to hibernate.  The following spring the caterpillars will feed again and then moult to the 4th instar after which they pupate hidden deep amongst the grass tussocks to emerge in late-April or early-May.   While habitat loss inland of suitably sunny, sparsely grassy, rocky sites has occurred, it is not believed to be the main reason for its dramatic decline.

Female Wall

The suggestion is that, with a warming climate, the first generation is emerging earlier in April and the corresponding second generation in late June and early July such that it continues to produce a third generation in late September. However, eggs laid by this third generation produce caterpillars that do not have sufficient time, before it gets cold, to reach the third instar, which is necessary for it to be able to over-winter.  This means that there is a significant loss to the population every time there is an attempt at a third generation.  The cooler habitats around UK coasts mean that there is less opportunity for the butterfly to produce this abortive third generation and thus they remain relatively common there.

Photos    Peter Bright

Strawberry Line Bird Survey

Those keen on wildlife will be interested to see this report on breeding birds along the Strawberry Line.  It suggests that the concentration of breeding birds along the line is greater than in much of the farmland the route passes through – another reason to support the development of off-road paths.

Butterfly of the Week 19th August 2020

On the Beacon at the end of February 2019

Painted lady:  This is, perhaps, our most well-known migratory butterfly which arrives every year in the Spring or Summer. The adult butterflies breed here, and their offspring are being increasingly recorded as flying south again in the autumn.  Painted ladies are a very strong flying butterfly and have been shown to cross from sub-Saharan Africa to North Africa and to reach even the most northern parts of Europe.  Similar migrations occur across other continents.  Seemingly during the northern winter, Painted ladies breed in North Africa and the offspring of these head northwards spreading across southern Europe and may even arrive in the UK.

 

 

More usually this generation will breed across southern France and Spain and it is the offspring of this generation that continue northwards arriving in the UK in May.  Here they breed, with caterpillars feeding on various kinds of thistles and may go from egg to adult in as little as 6 weeks.  This next generation may then continue northwards to breed again.  In the Autumn something about the shortening days and falling temperatures triggers the newly emerged adult butterflies to head south.

Huge numbers have been recorded heading south and are able to once more return to the north African breeding grounds from which their great or great great grandparents left in the previous January.  This strategy is so successful that the numbers estimated to return are much greater than the numbers that left.  The benefit of this migration is believed to be related to a very effective wasp parasitoid that each year more or less exterminates any remaining north African Painted lady caterpillars.  Migration means that the butterfly can evade this parasite and the successfully returning butterflies can take advantage once again of the ideal breeding conditions in north Africa over the northern winter before the wasp parasitoid multiplies once more.  The extent to which sub-Saharan originating butterflies are part of the European annual immigration is not yet clear.  While the occasional overwintering butterfly has been found e.g. in Cornwall, it seems clear that, as it has no ‘hibernation’ stage and caterpillars die when the temperatures fall below 5oC, it does not survive to any useful extent in the UK. The numbers that arrive in the UK each year are hugely variable and are, presumably, related to the particular conditions in the breeding grounds along their migration routes.  2009 and 2019 were the last ‘Painted lady years’ in which large numbers arrived in the UK.

 

This year a few have been seen in the Parish, but it has been only the odd one here and there.  The fashion for purchasing captive bred caterpillars means that more people can see these wonderful animals up close and personal, but complicates knowing whether any particular butterfly has come from North Africa or from a local butterfly farm. They are a spectacular butterfly, and all the more so, because of their entirely migratory life history.

Photos  Peter Bright